Some cartridge series fit more than one pen. In this catalog those tips are listed on every compatible model page so you can find them from the instrument you already own. The tip name (for example a shared bay series) matters more than which page you arrived from.
Before you assume two pens share a tip, compare the empty bay and the connector on a known-good cartridge. Shared listing means we have confirmed the same tip family for those models — it does not mean every accessory for one pen fits the other.
If you stock both pens in a shared series, you can often consolidate purchasing on that tip family. Still keep labels clear in your warehouse so staff pick the correct series when a customer names the pen instead of the tip.